1. Field of the Invention
The present invention relates to a zwitterionic lipid compound and uses thereof, particularly, to a zwitterionic lipid compound, which can be synthesized easily, which has high biocompatibility, and which has high biodegradability, and to the uses thereof utilizing its excellent molecular assembling characteristics such as a surface modifying agent, a dispersion stabilizing agent, a drug carrier and an oxygen carrier.
2. Description of the Related Art
Choline-type phospholipid such as diacylglycero-phosphocholine is widely used as a zwitterionic lipid that forms a vesicle. It is known to the art that the zwitterionic lipid forms a stable bilayer membrane by the electrostatic interaction performed between the polar head groups thereof and, thus, the zwitterionic lipid is utilized as a main component of the vesicle.
The properties of the hydrophilic group which the lipid, constituting the membrane of the vesicle, has, are reflected in the physiochemical and physiological properties of the vesicle. For example, if a lipid having polyethylene glycol or saccharide in the hydrophilic part is mixed at an arbitrary ratio, the residence time of the vesicle in the blood is changed. Also, it is possible to increase the accumulation capability of the vesicle on a specified site if various saccharide materials, antibodies, proteins, oligopeptides, etc., are supported on the surface of the vesicle. However, vesicles containing, as the main component, the conventional choline-type phospholipid are used in any of these fields, and a suitable substitute lipid that can be used in place of the choline-type phospholipid has not yet been put into the practical use.
The saturated phospholipid is high in the cost of the raw materials thereof, complicated in synthesis, and necessitates a column in purification, and thus is highly costly. Accordingly, where the vesicle containing the saturated phospholipid as a main component of the membrane is used for administration to the living body, the use of the vesicle is limited to the use as a carrier of an expensive drug that is used at a very small dosage such as an anti-cancer agent. However, since the double chain zwitterionic lipid such as the choline-type lipid forms a stable molecular assembly, the zwitterionic lipid is expected to be used in various fields such as not only the administering agent to the living body in a large amount such as an oxygen carrier but also foods, perfumes, cosmetics, toiletries, and dyes.
Under the circumstances, an object of the present invention is to provide a novel zwitterionic lipid.